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Arm Mbed Cordio

Arm Mbed Cordio is an open source Bluetooth Low Energy (BLE) solution offering both host and controller subsystems, with abstraction interfaces for both RTOS and hardware.

The Cordio BLE host subsystem implements a single-mode BLE device supporting both single- and dual-chip systems. It is composed of the following components:

The Cordio stack implements a standard HCI for compatibility with off-chip BLE controllers when using the dual-chip system configuration. You can use wired transports, such as UART or SPI, to connect to off-chip BLE controllers. The single chip (in other words, SoC) configuration uses a "thin HCI" layer to connect the Cordio BLE host to the Cordio BLE controller.

The Cordio BLE controller subsystem implements the BLE Link Layer.

Both host and controller systems use the following abstraction interfaces for compatibility across various system dependent functions:

Getting started

Consult the Mbed OS Bluetooth documentation for more information.

For access to pre-adopted specification features, contact us at cordio-info@arm.com.


Mbed Cordio is offered with an Apache 2.0 license as part of Mbed OS.

About the documentation


This documentation is written for experienced embedded C software engineers, who may also have experience with Arm products and BLE applications but may have limited experience with Cordio software.


[1]: Bluetooth SIG, “Bluetooth Core Specification”, Version 5.1, January 21, 2019.

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